Final answer:
Blood enters the left and right coronary arteries directly from the aorta, which supplies the heart muscle with oxygen-rich blood (Option 2).
Step-by-step explanation:
The left and right coronary arteries receive blood directly from the aorta. Specifically, they branch off from the ascending aorta just superior to the aortic semilunar valve.
The left coronary artery arises from the left posterior aortic sinus, while the right coronary artery arises from the anterior aortic sinus.
These arteries are critical for supplying oxygen-rich blood to the myocardium of the heart.
They branch into smaller arteries and capillaries, facilitating the exchange of gases, nutrients, and waste products with the heart muscle cells.
Hence, the correct answer is: Aorta (Option 2).